Browsing by Author "Gumula, Ivan"

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    Antibacterial Properties of Phytochemicals Isolated from Leaves of Alstonia boonei and Aerial Parts of Ipomoea cairica.
    (Kabale University, 2024) Gumula, Ivan; Kyarimpa, Christine; Nanyonga, Sarah Kiwanuka; Kwesiga, George; Busulwa, George; Opio, Boniface; Heydenreich, Mathias; Omara, Timothy
    The leaves of Alstonia boonei and aerial parts of Ipomoea cairica are used for treatment of microbial infections among other ailments in African traditional medicine. The aim of this study was to investigate the antimicrobial phytochemicals in A. boonei leaves and Ipomoea cairica aerial parts to validate their traditional use in Ugandan herbal medicine. Methods: The plant materials were separately extracted using a dichloromethane/methanol (1:1) solvent system and subjected to repeated chromatographic separation to isolate pure compounds. The chemical structures of the isolated compounds were determined through 1 H NMR, 13C NMR and 2D NMR (COSY, HSQC and HMBC). The antibacterial activity of the extracts and pure compounds were assessed using the agar well diffusion method. Results: Chromatographic fractionation of the extracts yielded trans-fagaramide and a pentacyclic lupane-type triterpenoid, lupeol, from A. boonei, and friedelin from I. cairica. Trans-fagaramide was identified for the first time in the Alstonia genus while friedelin was identified for the first time in I. cairica. The isolated compounds demonstrated antibacterial activity, with trans-fagaramide showing a minimum inhibitory concentration (MIC) of 125 μg/mL against Pseudomonas aeruginosa and 250 μg/mL against Staphylococcus aureus, Salmonella typhi and Escherichia coli. Friedelin exhibited a MIC of 125 μg/mL against Escherichia coli and 250 μg/mL against Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi. Conclusion: The antibacterial activities observed in this study support the traditional use of A. boonei and I. cairica by indigenous communities in Uganda for treating microbial infections.
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    Antimicrobial potency of extracts from selected medicinal plants towards Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa
    (Kabale University Interdisciplinary Research Journal (KURJ), 2023) Buyinza, Daniel; Gumula, Ivan; Akampuira, Denis; Ninsiima, Herbert
    Antibiotic resistance has become a very big threat to the existing first line antibiotics. Some of the infectious pathogens are becoming multidrug resistant including Mycobacterium tuberculosis. This has necessitated social, scientific and financial interventions from key players. The strain this puts on the fragile health care systems of developing nations is frustrating. Scientific interventions have involved campaigns for improved hygiene, use of combination therapies and revived search for new drugs with different modes of action. It is on this basis that this research was conducted as phase I into the search for antibiotic agents from nature. This was done by screening several plant extracts to identify bioactive extracts that can be developed into drugs or purified for better active single molecules in the second phase. Extracts were obtained by cold percolation of pulverized samples of different dried plant parts using different mono-solvents. Agar diffusion and froth floatation were used to measure the potency of the extracts. Many of the screened extracts had good to moderate activities. Five of the plant species; Zanthoxylum chalybeum and gilletii, Diospyros abyssinica, Prunus africana, Peptadeniastrum africana and Blighia unijugata showed very promising activities (1.9 to 9.4 mg/mL) against Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The other species had moderate activity (10.6 to 47.5 mg/mL). The species (Albizzia coriaria, Maytenus senegalense and Kigellia africana) that inspired this research from literature only demonstrated moderate activity against all the tested organisms, probably due to antagonistic effect of the active compounds within the extracts. In conclusion, Z. chalybeum and gilletii, D. abyssinica, P. africana, Peptadeniastrum. africana and B. unijugata have a very strong potential for drug development and are recommended for use in the management of infections caused by the tested microbes and purification to isolate the individual active compounds for better formulation, standardization and drug acceptability.
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    Fighting the next pandemic: A phytochemical Approach from African flora - An overview
    (Society for the Advancement of Scienvce in Africa, 2022) Buyinza, Daniel; Gumula, Ivan
    Management of any pandemic requires a multidimensional approach with a hand from all players. At every break of a pandemic, there is always no immediate treatment and efforts are often devoted to social distancing, isolation/quarantine, diagnosis, and care with prospects to treat but with no clear medication. The approach has always been to permit the body to fight off the pandemic by boosting its immune system through selective diet and or food supplements as external immune boosters in addition to arresting symptoms. With the exception of COVID-19, the burden of HIV epidemic and seasonal flu pandemics, infectious disease outbreaks have mostly devastated developing societies. The use of herbal remedies to cure several kinds of human diseases has a long history in Africa. Various plant parts are used to prevent, dispel symptoms or regress deformities to normal. A portion of the pharmaceutical products currently being prescribed by physicians including opium, aspirin, digitalis, paclitaxel, docetaxel, vinblastine, vincristine, quinine, and artemisinin have a historic use as herbal remedies. African medicinal plants are rich in such natural bioactive metabolites with therapeutic values against several diseases including deadly fevers. The therapeutic properties of these metabolites are a factor of the type and amount of alkaloids, phenolics, flavonoids, quinones, saponins, and terpenes contained. Human ingestion of these bioactive trigger pharmacological effects like antiviral, anti-inflammatory, analgesic, antidiabetic, antimicrobial, anti-parasitic, and antioxidant effects, thereby arresting the causal or symptomatic effects manifested in the pandemics. Ethnomedical and phytochemical studies on the African medicinal plants have led to the isolation of promising antiviral, anti-inflammatory, anti-parasitic, analgesic, and antimicrobial metabolites. Our discussion in this chapter is premised on challenging Africans Scientists (ethnobotanists, phytochemists, microbiologists, and pharmacologists) to collaboratively intensify the search for phytochemicals as drug leads and explore options for developing these leads into functional medicines for the various diseases/pandemics devastating the continent.